Collapsible mandrel.



L. A. BARR. DECD. M. L. BARR, ADMlNlSTRATRIX.

COLLAPSIBLE MANDREL. APPLICATION FILED JUNE 28, 1915.

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L. A. R, DECD. M. L. BAR MINISTRATRIX. COLLAPSIBLE MANDREL APPLICATION F1LEDJUNE28,1915.

Patented Oct. 31, 1916.

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tin a LOUIS A. BARR, DIE-PITTSBURGH, PENNSYLVANIA; MARGARET L. BARR ADMINISTRA- TRIX 0F SAID LOUIS A. BARR, DECEASED.

COLLAPSIBLE MANDBEL.

I Specification of Letters Patent. Pa t cen'tceedl @0113, 31, llQlllfi,

Application filed June 28, 1915. Serial No. 36,731.

To all whom it may concern:

Be it known that ll, lLoUIs A. BARR, a resident of Pittsburgh,in the county of Allegheny and State of'Fennsylvania, have invented a new and useful Improvement in Collapsible Mandrels, of which the following is a specification.

This invention'relates I to a collapsible mandrel and particularly to a mandrel dea mandrel which may be collapsed in order to permit its withdrawal from a completed tube, and which when assembled is of sufficient strength and rigidity to fulfil all of the requirements of a, mandrel used in the formation of iron or steel tubes, that is suiticiently strong and rigid to have skelp wrapped around it and to be subjected to the action of the rolls in the formation of tubes by the lap weld process.

A further object of the invention is to provide a collapsible mandrel which comprises but few parts and which may have walls of such thickness that they will effectually withstand the heat incurred during the process of forming tubes, and the operating parts of which are of suflicient strength to withstand strain and rough usage.

A still further object is to provide a mandrel which may not only be readily collapsed, but which may also be re-assembled by a similar action and without the use of any tools.

The invention comprises the construction and arrangement of parts as hereinafter described and claimed.

In the accompanying drawings, Figure 1 is a longitudinal section through the mandrel taken on the vertical diameter thereof; Fig. 2 is a similar view but illustratingthe position of the operating parts when the mandrel is collapsed; Fig. 3 is an end View of the mandrel; Fig. 4 is a similar view showing themandrel in collapsed condition; Fig. 5 is an end View of a portion of the shell of the mandrel showing a modified form of connection between the smaller seg ment and the two larger segments of the mandrel shell; Figs. 6 and 7 are views respectively of the central bar and operating a sleeve of the mandrel illustrating the relative positions of the guiding members of the mandrel bar; Figs. 8, 9, 10, 11 and 12 illustrate a modified form of the invention; Fig. 8 is a lon itudinal sectional view through the modi ed mandrel on the vertical diameter thereof; Fig. 9 is an end view of the modified mandrel expanded; Fig. 10 is an end view of the same collapsed; and Figs. 11 and 12 are detail views of the means for attaching the mandrel bar and operating sheave to the inner surface of the mandrel shell. y l

The preferred form of the device comprises a pair of relatively large segments 1 and/ 2 which are connected at one edge by a plurality of hinges. 3 and a third segment 4 arranged in assembled condition of the mantlld tilli drel to enter between the free edges of segments 1 and 2 to form a complete cylindrical body. In collapsing the mandrel segment 4 is drawn inwardly toward the central longitudinal axis of the mandrel by suitable actuating means and the free edges 5 and 6 of the segments 1 and 2 are drawn toward each other until they come in contact at a point on the central vertical axis of the mandrel which is slightly lower than the point reached by the outermost portion of the are previously formed by the'segment 4.

It is thus seen that the transverse diameter of the mandrel is materially decreased and the vertical diameter of the same is also decreased though to a lesser extent.

Upon the pintles7 of the hinges 3 is mounted a spoke 8 which supports a centrally located solid bar 9 with which it is integrally cast or to which it is rigidly secured. This bar throughout a portion of its lengthis rovided with a slot 10 extending entirely therethrough in a vertical plane, and arranged to receive a guide 11 secured to the inner surface of segment 4 of the mandrel "wall. Surrounding the bar 9 is a sleeve 12, slotted at 13 to permit the extension of the guiding member 11 therethrough, and slotted throughout itsentire length at another point to permit the passage of spoke 8 and guide 11. The guide 11 consists of a plate shown as substantially rectangular in shape, and is rovided with one or more slots 14 incline at an angle from the plane of the diameter of the mandrel. Preferably,

two ofisuch slots 14'are provided in the guide 11, and through each of these slots I I passes a pin which is bolted or otherwise rigidly secured at'each end to the sleeve 12. At the. extremity, of each of the slots 14 nearest the central axis of the mandrel the slot is extended rearWardly to form a lockclined slots 14.

Each of the segments 1 and 2 of the mandrel wall is connected to the 'sleeve 12 by a suitable hinged arm. These arms as illustrated in Figs. 1 to 4 inclusive consist of links 17 having at each ,end an elongated eye 18 interlocking with eye-bolts 19 on the of the segment 4. The contacting surfaces inner surface of the mandrel wall and upon the surface of the sleeve 12. When the sleeve 12 is actuated to collapse the mandrel I by removing segment 4 from its circumference, the same action will draw segments 1 and 2 inwardly until their edges 5 and 6 contact, the connection between the elongated eyes 18 and eye-bolts 19. providing a slight amount of lost motion so that the segment 4 is permitted tostart upon its down- 1 ward travel before the segments 1 and 2 are drawn inwardly; The inward movement of the segments 1 and 2 decreases the horizontal diameter of the mandrel considerably, while the upper extremities of their edges 5 and 6 are loweredsufficiently along the vertical axis of the mandrel to break the contact at that point between the mandrel and the in- I ner surface of the completed tube. In order tore-assemble the mandrel the sleeve 12 is moved rearwardly upon the central bar 9,

in which action the guide pins 15 act in the slots 14 to raise thesegment 4 and to cause it to enter between the edges 5 and 6 of the segmentsl and 2 to reform the cylindrical body of the mandrel. In this action the arms 17 act to force the segments 1 and 2 outwardly and thereby assist the re-assembling' operation by opening a space into which the segment 4 may be introduced.

The hinges 3 may be of any desired form but are preferably strap hinges, as'shown, arranged with their leaves 20 'securedto'the inner surface of the segments 1 and 2 and I with their pintles 5 lying entirely inwardly of the inner surface of the mandrel, so that k 2 will not rotate outwardly an. appreciable the edges 21 and 22 of the segments 1 and distance when the segments 1 and 2 are drawn together, and therefore will not counterbalance the decrease in vertical diam- A eter of the mandrel caused bv the removal form of contacting surface is used the segments comprising the tubular body of the mandrel are formed separately by a casting operation and their contacting surfaces machimed in order to secure a good engagement and form a perfectly cylindrical body. The form of contacting surfaces shown in Figs. 1 to, 4 of the drawings is the preferred form since it provides an improved locking engagement between the segments which allows the segment 4 to be more readily inserted between the segments 1 and 2 in assembling the mandrel and somewhat increases therigidity of the mandrel when assembled, since most of the strain incurred in use of the mandrel will be circumferential. This engagement, moreover, allows the segments 1 and 2 to move inwardly toward the vertical diameter of the mandrel a slightly greater distance, and therefore permits either a greater decrease in the vertical and horizontal diameters of the mandrel when collapsed or permits a thickening of the mandrel wall while securing the same collapsed diameters of the mandrel as with the straight engagement between the side segments and the movable segment 4.

Marfdrels as thus formed may be made of as great a length as is found practicable without causing sagging of the mandrel when subjected to the heating effect of the skelp in forming the tubes. If the mandrel is to be made of considerable length, the central bar 9 is preferably provided with a spoke 8 at short intervals, and the vertical movable segment 4 is provided with a corresponding member or guide 11 for which additional slots 10 and slots and guiding pins are provided. The hinges 3 between the segments 1 and 2 of the mandrel are preferably spaced at short intervals in order to increase. the strength of the construction, and are also preferably formed of as heavy a construction as possible in order to give greater strength to the mandrel. It will be noted that the arrangement of the parts as described permits the mandrel wall to be formed of comparatively great thickness, and that the other parts called upon to resist strains, namely, spokes 8, guides 11, and the guide pins 15 may be of comparatively great thickness and strength. It will be noted that clearance is provided between tllllt pin 15 and the under surface of the segment 4, as shown in Fig. 3 of the drawings so that in the construction of the mandrel eitherthe thickness of the shell or the diameter of the pins 15 may be increased to suit the anticipated conditions of use. It is also obvious that the diameter of the bar may be decreased in its relative proportion to the diameter of the shell, as shown, in order to permit a greater degree of clearance within the shell.

In the modification illustrated in Figs. 8 to 12 inclusive of the drawings, an additional movable segment a is provided. This segment is securedto a guide 11 which enters a suitable slot 10 in the central bar 9 of the mandrel. Since the spoke Y is omitted in this modification additional arms are provided between the sleeve and bar and the inner surfaces of the segments 1 and 2 in order to secure a firm and rigid construction. Three arms are hinged on the interior of each of the segments 1 and 2, in any suitable manner, two of the arms 25 being hinged at their outer ends to the-sleeve 12 and the other arm 26 extendin through a suitable slot 27 in the sleeve and eing hinged to the bar 9Q Both ofthe arms 25 and the arm 26 are secured to the interior of the mandrel shell by means of the hinge 28, which has a lost motion connection in the elongated eye 29, the leaf or strap 30 of which is bolted to the inner surface of the shell. The two arms 25 at their opposite ends are secured to the surface of the sleeve by means of hinge 30 bolted to the sleeve through straps 31, while arm 26 is provided at its inner end with a hinge 32 secured to bar 9 by straps 83. In this construction both of the segments 4 and 4. are withdrawn from the circumference of the mandrel in collapsing the same and the vertical diameter of the mandrel is decreased a correspondingly greater amount than when only one segment is so withdrawn. The guides 11 and 11 are necessarily located at different points longitudinally of the mandrel as shown in .F ig. 8, are provided with slots 14 and 14 and guiding pins 15 and 15 corresponding to those illustrated in the other form of mandrel, the slots l4 being obviously inclined at an angle which is equal to that of the slot 14 but opposite in sense thereto. i

The operating parts of the mandrel are susceptible of a number of other modifications without departing from the spirit of the invention as set forth in the appended claims. For example, the arms 17 secured to the inner surface of the segments 1 and 2 and to the sleeve 12 may be supplanted by arms of the form illustrated in the modification described above, or similar arms may be utilized to withdraw the segment l from the circumference of the mandrel.

The mandrel described is readily collapsed and reassembled, and when assembled forms a strong and rigid construction. The mandrel wall, moreover, is of such thickness that it is not apt to sag when subjected to the heat of the skelp and the pressure .of the rolls during the process of forming tubes, and is also enabled to protect the operating parts in the interior of the mandrel from sticking or bending due to the overheating of these parts.

What I claim is 1. A collapsible mandrel comprising". a plurality of segments arranged to form a hollow cylindrical body, a bar supported in the interior of said body, a sleeve slidable upon said bar, a guide secured to the inner surface of one of said segments and arranged to enter slots in said sleeve and bar, said guide being provided with a plurality of angularly disposed slots, andpins secured to said sleeve and passing through the slots in said guide.

2.'A collapsible. mandrel comprising a plurality of segments arranged to form a iollow cylindrical body, a bar supported in the interior of said body, a sleeve slidable on said bar, a guide secured to the inner surface of one of said segments and passing through slots in said sleeve and bar, and a plurality of pins secured to said sleeve and arranged to extend through angularly disposed slots in said guide and in assembled position of the mandrel parts to enter locking notches in said guide.

3. A collapsible mandrel comprising a plurality of segments arranged to form a hollow cylindrical body, a bar supported in the interior of said body, a sleeve slidable upon said bar, a guide secured to the inner.

means secured to said sleeve and arranged upon actuation thereof to collapse the remaining segments of the mandrel wall.

4. A collapsible mandrel comprising a 'to collapse the remaining segments of the mandrel wall.

5. A collapsible mandrel comprising a plurality of segments arranged to form a hollow cylindrical body, a bar supported in the interior of said body, a sleeve slidab-le on said bar, a guide secured to the inner surface of one oi said segments and passing through slots in said sleeve and bar, a plurality of pins secured to said sleeve and arranged to extend through angularly dis,- posed slots in said guide and in assembled position of the mandrel to enter locking notches in said guide, and means secured to said sleeve and arranged upon actuation thereof to collapse the remaining segments of the mandrel'wall.

6. A collapsible mandrel comprising a continuous shell composed of a plurality of segments, a guide secured to one of said segments and provided with an inclined slot,

a pin-passingthrough said slot, and movable means arranged to support said pin and when moved to cause it 'to act upon said guide for lowering the same within said shell.

.7. collapsible mandrel, comprising a continuous shell composed of a plurality of segments, a guide secured to one of said segments and provided with an inclined slot, a pin passing .through said slot, movable means arranged to support said pin and when movedto cause it to act upon said guide for lowering the same within said shell, and arms secured to'said movable means and the remaining segmentsof said shell for collapsing said remaining segments.

hollow cylindrical body divided into body segments and wedging means, .a bar supported interiorly of said body, a sleeve slidable on said bar, means on said sleeve connecting the same to said wedging means and arranged upon actuation of said sleeve to withdraw said wedging means positively from the mandrel shell without tending to collapse said body segments, and after said withdrawal to act upon said body segments to collapse the same. b

10. .A collapsible mandrel comprising a shell divided into body segments and 'a wedge segment, a bar mounted centrally of said shell, a sleeve on said bar and having connection with said wedge segment arranged to withdraw the latter upon actuation of said sleeve, and means for collapsing each of saidbody segments comprising a pair of interconnected arms pivoted to said bar and sleeve respectively and having a lost motion connection with the interior of said body segments.

11. A collapsible mandrel comprising a ing through said slots, and means for colllapsing each'of said body segments comprising a pair of interconnected arms pivoted to said bar and sleeve respectively and having a lost motion connection with the interior of said body. segment.

In testimony whereof, I set my hand.

LOUIS A. BARR.

Witnesses:

GLENN H. LEREBGHE, WILLIAM B. WHARTON.

have hereunto 

